ML17298B135

Forwards Request for Addl Info Re Isolation Devices Used in Reactor Protective Sys.Response Requested within 2 Wks of Ltr Receipt

ML17298B135
Person / Time
Site:	Palo Verde
Issue date:	07/25/1984
From:	Knighton G Office of Nuclear Reactor Regulation
To:	Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
References
NUDOCS 8408090483
Download: ML17298B135 (12)

Text

~UL 25 1984 Docket Nos.:

50-528/529 and 50-530 DISTRIBUTION

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RRC PDR Local PDR PRC System NSIC LB83 Reading JLee MLicitra OELD, Attorney ACRS, (16)

EJordan NGrace Mr. E.

E.

Van Brunt, Jr.

Vice President - Nuclear Projects Arizona Public Service Company Post Office Box 21666 Phoenix, Arizona 85036

Subject:

Request for Additional Information - Palo Verde As a result of the staff's review of Amendment No.

12 to the

FSAR, we have identified the need for additional information relating to isolation devices

.used within the Palo Verde reactor protection system.

In addition, further information will be required for the staff to complete its review of control system failures due to the effects of high energy line breaks.

The specific information required is identified in the enclosed request and has been discussed with Mr. Hike Jones and other members of your staff.

'We ask that you provide the requested information and that you advise us within two weeks of receipt of this letter as. to when the information will be sub-mitted.

If you have any questions regarding this request, you should contact Manny Licitra, the Licensing Project Manager.

Sincerely,

Enclosure:

As stated cc:

See next page George W. Knighton, Chief Licensing Branch No.

3 Division of Licensing DL:LBB3f/

DL' MLicitra/

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Palo Verde Mr. E.

E.

Van Brunt, Jr.

Vice President - Nuclear Projects Arizona Public Service Company P. 0. Box 21666 Phoenix, Arizona 85036 Arthur C. Gehr, Esq.

Snell

& Hilmer 3100 Valley Center Phoenix, Arizona 85073 Hr. James M. Flenner, Chief Counsel Arizona Corporation Commission 1200 West Washington

Phoenix, Arizona 85007 Charles R. Kocher, Esq. Assistant Counsel James A. Boeletto, Esq.

Southern California Edison Company..-

P.

Q.

Box 800

Rosemead, California 91770 Ms. Margaret Walker Deputy Director of Energy Programs

'conomic Planning and Development Office 1700 West Washington Phoenix, Arizona 85007 Mr. Rand L. Greenfield Assistant Attorney General Bataan Memorial Building Santa Fe, New Mexico 87503 Resident Inspector Palo Verde/NPS U.S. Nuclear Regulatory Commission P. 0.

Box 21324 Phoenix, Arizona 85001 Ms. Patricia Lee Hourihan 6413 S. 26th Street Phoenix, Arizona 85040 Regional Administrator - Region Y

U. S. Nuclear Regulatory Commission 1450 Maria Lane Suite 210 Walnut Creek, California 94596 Kenneth Berlin, Esq.

Winston

& Strawn Suite 500 2550 h1 Street, NW Washington, DC 20037 Ms. Lynne Bernabei Government Accountability Project of the Institute for Policy Studies 1901 gue Street, NW Washington, DC 20009 Ms. Jill Morrison 522 E. Colgate Tempi, Arizona 85238

ENCLOSURE ICSB RE UESTS FOR INFORMATION I.

ISOLATION DEVICES USED IN REACTOR PROTECTIVE SYSTEM Amendment 12 to the Palo Verde FSAR includes a revision to Section 7.2, "Reactor Protective System."

The information states that the Core Pro-tection Calculator (CPC) system and Core Element Assembly Calculators (CEAC) will provide their outputs and a number of their inputs to the Plant Monitoring System (PMS) which is considered to be nonsafety-related.

Fiber-optic data links are to be used for this interface.

The staff understands that this interface will be mono-directional (i.e., signals from the protection system CPCs to the PMS).

Paragraph 4.7.2 of IEEE 279-1971 permits the use of isolation devices to I

transmit signals from protection systems for use in nonsafety-nelated systems such as the PMS.

Acceptance of the design interface described above will be predicated upon the satisfactory qualification of the I

electrical isolation devices that are to be used to maintain appropriate electrical independence.

Information supplied to date is insufficient to determine whether the fiber-optic isolation devices are qualified for its application.

Therefore, please provide information to ensure that any electrical failure applied to the isolation device output will not degrade below an acceptable level the operation of the circuit connected to the input.

As a minimum, please provide:

1.

Detailed information (including drawings) to describe the physical implementation of the subject isolation devices I

into the reactor protection system design.

This should

k

W include specific information on the physical design and electrical characteristics of the isolation device itself.

2.

A description of the specific testing or analyses performed to demonstrate that the device i s acceptable for its appl i ca-tion.

This description should include a discussion of the system mock-up considered including elementary drawings where necessary to indicate the design configuration and how maximum credible faults (including continuous phase-to-phase short circuits, phase-to-ground short ci rcuits, and the application of continuous external high voltages) and voltage transients were applied or considered.

3.

Oata to verify that the maximum credible faults and tran-sient voltages considered were the maximum voltage/current to which the isolation device could be exposed, and define how the maximum values were. determined.

t 4.

Information to verify that the maximum credible faults and transient voltages were considered in both the transverse (line-to-line) and common (line-to-ground) modes.

5.

Oata to define the pass/fail acceptance criteria.

6.

Information to verify that the isolation device is classified as part of the protection system (i.e.,

verify that the device is safety-related; environ-mentally qualified in accordance with 10 CFR 50.49, and seismically qualified).

7.

Data to verify that the effects of electrostatic coupling and electromagnetic interference were considered.

II.

CONTROL SYSTEM FAILURES DUE TO HELBs NRC 22293 Reference 1:

APS letter from E.E.

Van Brunt, Jr. to G. Knighton of NRC dated November 16, 1983.

Reference 2:

APS letter from E.E.

Van Brunt, Jr. to.

G. Knighton of NRC dated February 14, 1984.

By letter (Reference

1) dated November 16, 1983,it is stated t)at the I

combined failure of the steam bypass control system (SBCS) and'eac-tor regulating system (RRS) during a steamline break (SLB) event is not credible since there are interlocks within these control. systems which prevent simultaneous operation of the worst-case failures (those which exacerbate event consequences) for these two control systems.

The additional information provided in Reference 2 confirms that the SLB event will not affect the control system interlocks circuitry. It

. is understood that only the input parameter channels to both the SBCS and RRS will be affected by a

common SLB event.

The staff finds this acceptable pending the satisfactory resolution of the issue described below related to the actual design associated with the subject inter-locks.

The information provided in Reference 2 states that should the SBCS produce a quick opening signal, an automatic withdrawal prohibit (AWP) signal would be generated to the control element drive mechanism con-trol system (CEDHCS) such that the RRS withdrawal demand would be blocked.

The staff reviewed Section 7.7 of the PVNGS and CESSAR FSARs to,obtain a better understanding of the SBCS and RRS interface with the CEDI1CS.

Upon review, it was revealed that no discussion of the SBCS/CEDt1CS interface exists.

Therefore, the staff requests that the following specific information be provided:

l.

Detailed elementary drawings and electrical schematics to show the interaction, of the RRS and SBCS output signals with the CEDHCS.

This should clearly show the interface of the SBC)

- AWP signal with CEDHCS which is to be used to block the RRS demand for withdrawal of control element assemblies=(CEAs).

The drawings should be highlighted and/or annotated as necessary for clarity.

2.

Information to verify that should the RRS demand for with-drawal signal exists, a subsequent SBCS AWP, signal will block the RRS demand signal and will result in the di scon-tinuation of CEA withdrawal.

Drawings to be provided as part of item I above should clearly show this.

Again, please highlight and/or annotate where necessary.

3.

Clarify the statement (Reference

2) that "The SBCS generates an AWP signal whenever a

SBCS demand for opening the turbine bypass valves exists...." as it relates to the quick opening signal (i.e., will any open command signal - Nodulation Node, guick Open Node - give AWP or just the guick Open Mode signal).

The staff also recommends that the FSAR should be revised to describe the interaction of the SBCS with the CEDMCS and its blocking function associated with the RRS outputs to the CEDMCS.

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